Coolant temp gauge fluctuates

[Daniel Brazzle]

Hey guys I have a 2015 GMC Sierra 1500 5.3. I have noticed my temp gauge will get to 210 and then drop a little and then go back to 210 and keep repeating it. My 2011 stayed at 210 no matter what. Is this normal on these newer trucks I have heard other people’s do it too. It don’t even drop to the next mark below 210 just about halfway between the next mark and 210.

[2018GMC]

Hey guys I have a 2015 GMC Sierra 1500 5.3. I have noticed my temp gauge will get to 210 and then drop a little and then go back to 210 and keep repeating it. My 2011 stayed at 210 no matter what. Is this normal on these newer trucks I have heard other people’s do it too. It don’t even drop to the next mark below 210 just about halfway between the next mark and 210.

There was a recall for over cycling thermostats (and new housing) causing radiator failures. 2014 - 2015 I believe. Either that or you have a failing thermostat

[Daniel Brazzle]

14 hours ago, 2018GMC said:

There was a recall for over cycling thermostats (and new housing) causing radiator failures. 2014 - 2015 I believe. Either that or you have a failing thermostat

I have a new thermostat coming. I haven’t lost any coolant so do I need to worry about the radiator 

[acc412]

1 hour ago, Daniel Brazzle said:

I have a new thermostat coming. I haven’t lost any coolant so do I need to worry about the radiator 

ITs the thermostat. had the same issues @ 62,****** on a 2016 5.3. Replaced it it under 20 mins and it was back to steady as a rock @ 210.

 

its a lazy thermostat. 

[Daniel Brazzle]

12 minutes ago, acc412 said:

ITs the thermostat. had the same issues @ 62,****** on a 2016 5.3. Replaced it it under 20 mins and it was back to steady as a rock @ 210.

 

its a lazy thermostat. 
Did it do any da mage to the radiator?

 

[acc412]

11 minutes ago, Daniel Brazzle said:

 

Not from what i've seen

[Daniel Brazzle]

7 hours ago, acc412 said:

ITs the thermostat. had the same issues @ 62,****** on a 2016 5.3. Replaced it it under 20 mins and it was back to steady as a rock @ 210.

 

its a lazy thermostat. 

How many miles have you put on it since you replaced the thermostat 

[acc412]

8 hours ago, Daniel Brazzle said:

How many miles have you put on it since you replaced the thermostat 

Maybe 150.

[Daniel Brazzle]

31 minutes ago, acc412 said:

Maybe 150.

Ok I haven’t lost any coolant that I can tell nor have I smelled any. I hoping it hasn’t hurt my radiator. Should have the new thermostat Saturday. 

[acc412]

21 minutes ago, Daniel Brazzle said:

Ok I haven’t lost any coolant that I can tell nor have I smelled any. I hoping it hasn’t hurt my radiator. Should have the new thermostat Saturday. 

Make sure its OEM.

Are you getting just the thermostat or the entire housing?

 

 

[Daniel Brazzle]

1 hour ago, acc412 said:

Make sure its OEM.

Are you getting just the thermostat or the entire housing?

 

 

I’m getting the entire housing OEM

[acc412]

31 minutes ago, Daniel Brazzle said:

I’m getting the entire housing OEM

Good. Here is an easy way to do it and how I did it.

 

1) Let the engine cool Down

2) Clamp the upper radiator hose going to the thermostat WITH HOSE CLAMPS (NOT VICE GRIPS)

3) Take off the hoses

4) Unscrew the bolts x3

5) Clean surface

6) Grease O-Ring and install

7) Tighten down (hand tight)

8 ) Re-Connect Hoses

9) Release Clamp

10) Fill reservoir uncapped

11) Let it run and do its work

12) Refill. 

[Daniel Brazzle]

1 hour ago, acc412 said:

Good. Here is an easy way to do it and how I did it.

 

1) Let the engine cool Down

2) Clamp the upper radiator hose going to the thermostat WITH HOSE CLAMPS (NOT VICE GRIPS)

3) Take off the hoses

4) Unscrew the bolts x3

5) Clean surface

6) Grease O-Ring and install

7) Tighten down (hand tight)

8 ) Re-Connect Hoses

9) Release Clamp

10) Fill reservoir uncapped

11) Let it run and do its work

12) Refill. 

Should I be worried that it has done damage to the radiator?

[MaverickZ71]

Think about this.  When you start the vehicle, if it has sat overnight, the coolant temp is ~ the temp of where the truck is parked.  Anywhere between 185F and 235 is considered normal operating temperature, with 260 and above overheating.  So if you're not seeing above 210, how could your radiator have possibly been damaged by the thermostat??

Edited June 24, 2020 by MaverickZ71

[Daniel Brazzle]

18 minutes ago, MaverickZ71 said:

Think about this.  When you start the vehicle, if it has sat overnight, the coolant temp is ~ the temp of where the truck is parked.  Anywhere between 185F and 235 is considered normal operating temperature, with 260 and above overheating.  So if you're not seeing above 210, how could your radiator have possibly been damaged by the thermostat??

I thought the the same thing but there is a TSB for over cycling thermostats which cause radiators to leak